1. Field of the Invention
This invention relates to a dock monitoring system and more particularly to improvements relating to transmission and processing of data in a monitoring system such as used for monitoring operations at a truck docking facility to obtain improved safety and traffic control and to facilitate scheduling and planning. The invention facilitates installation of equipment, provides increased reliability and minimizes manufacturing and other expenses.
2. Background of the Prior Art
As disclosed in my aforementioned prior application, systems have heretofore been provided for controlling operations and indicating operations at truck docking facilities. The Hahn U.S. Pat. No. 4,692,755 discloses a system in which signal lights are provided on the inside and outside of a dock facility to give dock personnel and truck drivers clearly visible indications of when it is safe or unsafe to load or unload a truck or to park or remove a truck, and to provide other safety features. An improvement of the system of the Hahn Patent is disclosed in the Trickle et al. U.S. Pat. No. 4,843,373 issued Jun. 27, 1989. The system of the Trickle et al. patent includes a programmable control unit which is versatile and provides various safe and reliable modes of operation, being also operable to perform diagnostic operations. These systems have produced increased safety and efficiency in loading and unloading operations with the result that problems and the possibilities for other improvements have not been recognized.
In my aforesaid prior patent, a system is disclosed which resulted in part from a discovery and recognition of problems with existing systems, particularly with respect to safety and efficiency problems which occur in many systems, especially in systems in which there are a large number of truck loading/unloading positions. A monitoring system is provided for installation at a multi-position docking facility which includes a locking device at each position for restraining a truck against movement during loading/unloading operations. The system is relatively inexpensive but permits a controller or dispatcher at a multi-position truck docking facility to easily and instantaneously obtain information as to the current status of the locking device at each truck unloading position and, in addition, to obtain information as to the length of time that each operated lock device has been in its locked condition.
Information from each loading position on the dock is received from sensing devices located in each position. Each time a change occurs in the status of any one of the positions, the change is recorded so that over time a picture of the comings and goings as a whole is built up. Such information is usable on a day to day basis and is also accumulated over longer periods.
The system of my aforesaid prior application has other important advantages and features which are disclosed in detail therein. A data processor is used which is preferably a standard type of personal computer and associated keyboard and monitor available commercially at relatively low cost. The data processor is operable by a keyboard and is adapted to receive signals placed in each of the loading/unloading positions of a loading dock facility. The sensors coupled to the data processor include lock condition sensing means for developing locked and unlocked signals respectively corresponding to the locked and unlocked condition of a truck in the at each of the positions.
The data processor is operable to continually process signals from the lock condition sensing means and includes a display screen to enable a plurality of types of data to be displayed. The types of data available include the current lock condition data which shows the current status of each of the lock conditioning means and the load time data showing the time of development of each locked signal and the data processor may also be coupled to truck sensing means for developing empty and in-door signals corresponding to the existence or otherwise of a truck in each of the loading/unloading positions.